1. Field of the Invention
The present invention relates to external skin wound fasteners that are employed for rapid closure of skin wounds by bringing sides of the wound into apposition. Apposition is a layered formation of superficial and deep soft tissues beginning at the skin surface. Hard tissue as cartilage, bone, enamel, dentin, and cementum may lie beneath the apposition and thus can benefit by being stabilized by fasteners securing the tissue above. The fasteners may be clips, clasps or uniters.
2. Description of Related Art
Skin wounds may be closed with surgical fasteners (clips and skin staples), sutures, Ethicon dermabond, or Gecko-inspired surgical tape.
Skin wounds of shallow depths (3.9 mm) are closed by skin staples, but cannot close deep wounds. Deep wounds are closed now with sutures in layers and only the surface is stapled with staples.
Ethicon dermabond is a skin bond glue—liquid that hardens in contact useful only for small tension free cuts (such as for children who are afraid of needles). Gecko-inspired surgical tape is made of a biodegradable elastic polymer and is suitable to patch wounds in organs such as the liver or heart.
Surgical fasteners (including clips and staples) and mentioned in U.S. Pat. No. 5,618,311 permit the surgeon to rapidly close a wound with a mechanical fastener, which holds the tissue together while the wound heals. These present day surgical fasteners however reach only to shallow depths and cannot appose bulky tissue masses. Both metallic and non-metallic fasteners are in common use. Some of the non-metallic fasteners are formed from bio-absorbable resinous materials such as blends of lactic acid/glycolide copolymer. Plastic materials of this type are widely known and commercially available under the trade names of “POLYSORB” and “LACTOMER” plastic. Typically fasteners made from these materials lose a substantial portion of their tensile strength after a few weeks of exposure to human tissue. After deployment in a mammalian body, the fasteners fragment and the pieces are metabolized by the body and therefore dissolve over time.
According to U.S. Pat. No. 5,618,311, the principal advantage of surgical stapling is the speed with which a wound or incision can be closed. However, in certain surgical procedures it is desirable to close the skin wound with sutures lying completely in the dermis layer. This form of subcuticular suturing minimizes the occurrence of visible scarring. However, such subcuticular suturing is very tedious and is very time consuming to perform. Surgical staplers and clips are not available for performing this type of closure.
U.S. Pat. No. 5,618,311 proposed a biodegradable surgical fastener having noninterlockable members. The fastener comprises a first arm and a second arm integrally interconnected to each other. Each arm has a distal prong such that each of the distal prongs are directed toward the other arm. Also proposed is a surgical fastener applicator for applying surgical fasteners having arms each with a prong. This staple-gun like applicator extrudes the biodegradable fastener horizontally to stay parallel to the skin surface in the dermis of the skin, and it is thus not meant to appose in vertically made deep tissue wounds.
Such an applicator comprises a fixed handle, a movable applicator lever mounted for motion with respect to said fixed handle, an applicator nose mounted to the fixed handle for storing a plurality of the fasteners and for positioning a fastener at the distal end of the applicator nose, spreader pins located proximate the applicator nose and contacting the fastener, and means connected to the spreader pins and the applicator lever for translating the movement of the applicator lever to the spreader pins. As the applicator lever is actuated, for example, when it is moved into the fixed handle, the spreader pins first apply pressure on the arms to spread apart the prongs of the fastener and subsequently release the pressure on the arms to allow the prongs to approach each other. The applicator can further have squeezer jaws located proximate the applicator nose and coupled to the movable applicator lever so that motion is translated from the applicator lever to the squeezer jaws when the applicator lever is actuated, for example, when the lever is moved into the handle. The squeezer jaws first open to allow the prongs to be spread apart by the spreader pins and subsequently close to apply pressure on the arms to bring the prongs of said fastener together after the spreader pins release the pressure on the arms to allow the prongs to approach each other.
It is desired to provide a surgical fastener suited for closing, at a rapid rate, deep wounds. It is further desired that such a surgical fastener be quickly removed when desired to do so. It is desired to not only close in the dermis, but for deeper wounds, to close fascia and muscle layers all at once if need be.